Sure, Dad always warned you not to eat the yellow snow when you were a kid, but even the pretty white stuff can harbor some nasties. Yet, for individuals traversing the back-country in the winter–such as cross-country skiers, first-responders and avalanche rescue crews–melting snow for drinking water is an ideal, if time-consuming, way to avoid carrying around a lot of bulk in the form of liquids. William VanZee of Brooklyn, New York, has conceived of a safe, fast snow-drinking solution: the Pure Melt Bag.

This device consists of a waterproof, roll-top interior bag–similar to the dry-bags used on river expeditions–which fits inside a backpack shell equipped with a solar heating element and a charcoal filter. Simply stuff the interior back full of snow, roll the top down into the secure position, place it in the back-pack shell and away you go along the trail. As you move, solar energy gained from the sun on your back heats up the wire element, melting the snow. On its way down to the tap at the bottom of the backpack, the water passes through a charcoal filter, removing impurities.

image via William VanZee

The Pure Melt Bag can be used by itself or strapped on the outside of a larger backpack; it features a removable nozzle and charcoal filters (which must be changed out according to manufacturer instructions in order to maintain the bag’s purifying functions).

image via William VanZee

This seems like a great concept for those who spend a lot of time hiking in the winter–for those of us who just frolic in the white stuff now and then, probably, not so much.